Tunnel kiln



Feb. 26, 1924. 1,485,109

H. w. H. BETH ET AL TUNNEL KILN Original Filed Nov. 27. 1920 FqZ WITNESSES I 7 r L mvsn'rons gig) T 1 l/qzyo Mdflcik.

3a ail/012580001101:

. f F ATTO NEY Patented Feb. 26, 1924- umrso STAT ES'. PATENT' OFFICE.

HUGO W. H. BETH AND MILTON F. BEE CHER, OF WORCESTER, MASSACHUSIJ'L'ID, AS-

SIGNORS TO NORTON C TION or mnssscnfisn'rrss OMPANY, Q]? WORCESTER,

MASSACHUSETTS, A CORPORA- reams. KELNI Application filed November 27, 1920, S g rla1 No. i26,7l2. Renewed January 7, 1924.

To all whom it may concern:

Be it known that we, HUGO WQH. BETH and lllILTON F Breanne, citizens of the United States of America, residing at Worcester, in t 1e county, of \Vorcester and State of lilassachusetts, have invented certain new and useful Improvements in Tunnel Kilns, of which the following is a full, clear, and exact specification. f

This invention relates to tunnel kilns of the t 'pe exemplified by the patent tq'Dre ssl6! i 0. 1,023,628 of April 16,1912, and more particularly to kiln cars and equipment for supplorting and conveying ceramic ware throu the tunnel kiln. I

Tunnel kilns of t iis ty e involve alonitudinal heatingv chamber avin'g benches for supporting heating muflles thereon and i a and conveyin ceramic .ware through the heating zone the kiln longitudinal passage for the kiln carsI be.

tween the.be1 1chcs so arranged that the; car wheels, and frame will be below the'heating zone and shielded from the intense heat by a body of-rofractorymaterialon :thei'car frame.- The ninflles in t verse air circulating pass ges adapted to w operate with a similar transvei passage in the car body to circulate the heated airjbeneath the were and around the heating mufiles. 1 a the cars heretoforei tilized in this kiln, the car top made of th usual refractoryirpoor conducting. fire clays has been mounted u onse arated transverse beams and provi ed wit spaced openings communic tin with-the transverse; passages. Since not cars are periodically removed from thokiln and so subjected to repeated heat g and cooling treatmen 7 these our trips; end to warp und-otherwisd become d'efective and so render it difiicultlto set t 1e cylindrical butts and sag rs hereto: for! em loyed to support the co. ami were duringring and require the ca fulijleveb' ling of each stand of saggersl Fn 'therinore,

aniuneven heat distribution results from the" facts that someof the car top 011' nin gs are p rtly covered and free circulati n qflthe a r partially restricted b the sag rs, while hers are wholly expose and I he 1ve our top and its supports banidinary fire cla and therefore poor h at con; ductors, retar somewhat the conduction of kiln have transproperly and to provide a kiln our construction and arrangement offiparts' which is well ada ted for setting and ring ceramic articles, w 'ieh will be economical of space and permit the setting of the maximum number of articles non each gear, which will insure more uniform heating of the were during firing, and which otherwise will increase the general eiliciencyfand practicability of kilns of this 1 gl fith this and other objects in view, as will be apparent from the following disclosure, our unvention resides in the combination of parts as'described herein and covered b the claimsappendedhereto In 1. 1e drawings: f K Figure 1 is a side elevat' kiln. car embodying this i ntion' Fig. 2 is a top plan view df the car; and Fig. 3 is an end View oi; :car showing the unnel kiln walls n of tunnel and heatin'g, mufitos.

In the drawings, which illustrate one embodiment of this invention; we have therein diagrammatically sh \va a tunnel kiln (see Fig.3) which inv lves the masonry work made of suitable refractory material having an arched roof indicatediin part at 1 1 and flat benches 12 for supporting the ,mntlles 13 thereon,

The benches 12 are spaced by a longitudinal passage 14; within which the kiln cars traverse, those cars being adapted to ryln upon suitable rails 15 supported on the liner of the kiln. In the form illustrated this kiln car comprises a metal frame wor suitably mount -upon wheels 21 in accordance with any suitable construction jas is well known in this art. The refractory th ,danfraine 0 comprises hollow refracb ocks 224, which may be filled with suitablemowdred refractory heat insulating" materil' 23 such as infusorial earth.

These bloc s 22 are of jointed shape adapted peistructure mounted upon to interlock and interfitwith each other to rovide a solid and substantial foundation or the ceramic ware.

Since it is necessar that the ceramic ware be uniformly hcate and to prevent the kiln car cooling the ware adjacent it because of the car body being massive and absorbing heat but slowly due-to its location in the unheated assage below the muilie benches, .We rovise a, car to 24 of refractory materia which has a iigh heat c n of solid bricks c ductivity. As a specific example of one t pe of block which is 'ada ted for this purpose,

we may utilize crystal ine alumina. or silicon carbide granules which have been bonded by suitable ceramic bonds well known in the refractory art, suchas a mixture of suitable ball clays so proportioned as to bondthe granules into a com act, dense structure ca:

ableof resisting eavy loads, as well asgh tem rature conditions in the kiln. A's illustra inFig. 3 this car top is made up osely positioned and'joined by a refractory cement, which may be similar in com tion .to the bricks, to form a plain and imperforated surface. This trip is substantially on a. level with the top of ,the

may directed across the car beneath the En order that the ware, such as grinding wheels, gmay be subjected to even tempera-.. ture conditions, we support them in suitable saggers 25 of'rectangular cross section, as.

illustrated in"Fi, rs. 1 and 2. Each sagger has an open top'26 and isso shaped and constructed that it may be set upon theopen the stacks of the saggers and to permit the circulation of gas thercbetween. The saggers are mounted on the bricks 27 with their sides parallel to the car side and spaced apart both lon 'itudinally and transversely so that hcatc air may circulate freely around each stack. This spacing may be maintained by suitable means such 31s the refractory blocks 28 which engage the saggcrs, as illustrated, and steady the pile. Since the upper portion of the kiln chamber tends to be hotter than the part adjacent the car top, we may inake the saggers 29 adjacent the car of a refractory material of high heat conductivity, such as ceramic bonded crystalline alumina or silicon carbide, and use the ordinary fire clay saggers so that heat from the muflies 30 for the top members of the stacks. By this arrangement and selection of kiln furniture of proper conductivities, we insure furnishing more heat to the are which is located in relatively cool positions and some- ,grhaqprotcct the ware in hotter portions of the in n frmn'the cli'ects of direct radiation of heat. In accordance with this inyention, we provide a tunnel kiln car and its associated equipment whichlargely increases theefiiciency of the kiln. Due to lowerin the car platform to the level of the muffii: bench, one may pile higher stacks or sag ers on the car than heretofore possible. A large economy furthermore results from the employment of open top saggers of rectangular cross section arranged in vertical spaced stacks, it having been found thatthe primary loss in setting space has been due to the use of round saggers as mordinarily employed in the grinding wheel industry for supporting-wheelson their Hat faces;

.The heat distribution is maintained more uniform than heretofore possible by separating the staelis of sa'ggers from on d so that the heatiln above the car other and from the car to ed air may traverse the top and directly incontact with the bottoms of thesaggers and circulate around each stack; The heat distribution is furthermore aided by the employment of bricks of hi h heat conductivity for the car'top and t e supporting blocks, these blocks being made of such material that they retain their sha 0 under the high heat conditions in the kiln and donot deteriorate under normal usage.

Having thus described our invention,

whatwe claim as new and'desire to secure by Letters Patent is: a I

1. In a tunnel kiln having ",ngitudinal muflie benches in the heating ch %1ber and a car traversing passage thereb ween, the combination therewith of a car comprising a wheeled support, an imperforate refractory body portion thereon having a. plane top disposed substantially on a level withv said benches, small refractory blocks 'of high heat conductivity spaced on said ear top so as not to obstruct the transverse flow of gases and stacks of refractory containers disposed on said blocks in spaced relation transversely and longitudinally 'of the car.

2. A tunnel kilncar cbmprising a wheeled support, a refractory body thereon havin a plane impertoratc top of ceramie'bonccd granules of high heat condiurtivit y, refractory blocks of high heat COIldllCllVlty spaced on said top and open topped saggcrs of rec- 'tangular cross section mounted on said blocks and spaced apart longitudinally and transversely 0f the car.

3. An apparatus for firing ceramic were in a tunnel kiln comprising a wheeled sup-.

port, a refractory body thereon having an imfperforate fiat car top, rows of stacks of re rectory containers spaced each wa from one another and small refractory bloc supporting said stacks on the flat car to and permitting a substantially free circu ation of heated gas' thereunder and between the stacks.

4. An a paratus for firing ceramic ware in a tunne kiln com risin a wheeled Support, a refractory bosy of ow conductivity thereon, an imperforate fiat top layer on said body of super-refractory material of high heat conductiyjtgn and rows of stacks of refractory containers supported on said top layer in s aced relation from each other and said top ayer to permit free circulation of heated kiln gas thereabout.

5. In combination with a tunnel kiln having a car passage, a muffle bench and a rnuflle thereon which has transverse air circulating passages, a car comprising a wheeled support, a refractory body thereon havin a plane imperforate top disposed just be ow said passages, stacks of open topped refractory receptacles of rectangular cross-section mounted on said car tops in spaced relation and means to hold the stacks spaced from each other and the car top for the circulation of heating gases around the stacks.

Signed at \Vorcestcr, Massachusetts, this 26th day of Nov., 1920.

HUGO W. H. BETH. MILTON F. BEECHER.

Certificate of Conw- It. ia horeby certified that in Letteri; Patent No. 1,485,109, granted February 26 1921, u n the application of Hugo W. H. Both and Milton F. Beecher, of W orqestor mohnsetts, for an improvement iii Tunnel Kilns, errors appear in the printed specification requiring correction as follows: Page 2, line 110, claiin 1, strike out the words an im erforate and insert instea the article a, and' line 111,, strike out the article u and insert the words an imper orate; and thltthp BflidfLBfi/BI'S Patent should be read with these wn'eotions t erein that the We mg :oonform to the' record of the case in the Patent Oflioe.

Signed ancleesled th s 1st day of April, A. D. 1924.

[512ml KARL FENNING,

A "an" flmminn'nmr of Patents. 

